Design And Development Of Pulse Signal Acquisition System Based On Micro-piezoelectric Sensor

In recent years,the traditional chinese medicine(TCM)has been attracted a great deal of attention.The core of the TCM is the TCM pulse diagnosis,however,the TCM has been making the finger as the medium since ancient times,which has a lot of limitations.Therefore,basing on the item of the tutor,this paper designs and develops a pulse acquisition system.This paper includes the following work:understand the basic knowledge of the pulse,select sensor,circuit board design and proofing,data transmission and collection,restore and display pulse signals,digital filtering of signals.The pulse signal is successfully collected at last,and the pulse graph is completely showed,the design and development of pulse collection system based on micro piezoelectric sensor is realized.This paper mainly launches from the following several steps:First,this paper debates the basic knowledge of TCM pulse and discusses the practical significance and the scientific research function of the research and development of pulse acquisition system.Then this paper selects the PVDF piezoelectric film and analyses the working principle and equivalent circuit of PVDF piezoelectric film,and explains why it is suitable for collecting pulse signal.Second,this paper designs the fore-end circuit board and completes the PCB drawing and proofing.The signal processing circuit is mainly to complete the signal pre-amplification,filtering,eliminating 50 HZ interference and voltage rise and so on,which includes AD620,OP07,OP27 and other chips.The main chip AT89S52 and AD module completes the signal analog to digital conversion.The PCB is completed in Altium designer and sent to the factory for proofing.Finally,with the help of USB to TTL serial module,the whole circuit board completes the communication with the host computer.Third,the main chip program is finished in the Keil Vision4 and sent to the microcontroller.Then the USB actuator is installed.Finally,through the USB communication module the PC accepts and saves the pulse data which is transmitted from the front circuit board.Using the MATLAB the PC restores the pulse data,theserial data is imported into the MATLAB through the MEX file.After disposing,the pulse signal of sphygmogram is displayed in the form of GUI interface.Fourth,this paper designs the butterworth filter to complete the further denoising of the pulse signal.On the basis of preserving the basic characteristics of the pulse,the sphygmogram becomes smoother,which is advantageous to the further analysis of the sphygmogram.Finally,the paper summarizes the pulse collection system,and take over how to ameliorate the design.